Disc brake for vehicles



Feb. 10, 1959 H. J. BUTLER nzsc BRAKE FOR VEHICLES Original Filed Nov.12. 1952 United States Patent DISC BRAKE FOR VEHICLES Henry JamesButler, Sutton Coldtield, England, assiguor to Dunlop Rubber CompanyLimited, London, England, a British company Original applicationNovember 12, 1952, Serial No. 319,972, now Patent No. 2,784,811, datedMarch 12, 1957. Divided and this application January 3, 1957, Serial No.632,280

3 Claims. (Cl, 188-73) This invention relates to disc brakes forvehicles, more particularly to disc brakes for motor vehicles and thelike, and is a division of my previous United States application SerialNo. 319,972 filed on November 12, 1952, now Patent No. 2,784,811,granted March 12, 1957.

Disc brakes for motor vehicles and the like generally comprise a disc,secured to a wheel or transmission shaft, and rotatable in a verticalplane. A non-rotatable housing straddles the disc at one location and isprovided with torque-absorbing pads of friction material and one or morefluid-pressure operated mechanisms for forcing the friction pads anddisc together in friction engagement to decelerate the vehicle or thelike. In many such installations the disc is secured to a wheel whichis, in turn, mounted on an axle shaft, and the housing is securednon-rotatably to a rigid part of the vehicle chassis. It has beenfoundthat the axle shaft deflects or bows when subjected to a suddenloading, e. g. on cornering the vehicle or running on a steeply camberedroad, with the result that the disc no longer rotates in a trulyvertical plane with respect to the rigid housing. The bowing of theshaft, due to forward component of the moving vehicle, is seldom in aplane at right angles to the ground surface, but may be inclined to oneside or other of said plane. The result is that the disc wobbles oroscillates to each side of its normal vertical plane. The friction pads,however, are constrained to move axially in the rigid housing, with theresult that on applying the brake, with the above condition prevailing,the efficiency of the brake is substantially reduced.

The object of the present invention is to provide an improved type ofdisc brake for road vehicles andthe like.

According to the invention, therefore, a disc brake assembly forvehicles or the like comprises a disc normally rotatable in a verticalplane, a non-rotatable housing having members on opposite sides of thedisc connected together adjacent a periphery of the disc, friction padsassociated with said members to frictionally engage the braking surfacesof said disc, a mechanism to effect said frictional engagement and anarticulated linkage to connect the housing to a non-rotatable member topermit substantially-axial movement of said housing relative to the discto enable said frictional engagement to be made and also to permittilting of the housing to accommodate wobbling or oscillation of saiddisc from said vertical plane.

According to the invention also a disc brake for vehicles and the likecomprises a disc normally rotatable in a vertical plane, a non-rotatablehousing comprising a pressure member and a reaction memberaxially-aligned on opposite sides of the disc and covering only a minorportion of the braking surfaces thereof and connected together by meansextending axially adjacent a periphery of said disc, a first pad offriction material secured to the pressure member to frictionally engageone face of the disc, a second pad of friction material to frictionallyengage the other face of the disc, a fluid pressure operated mechanismassociated with the reaction mem her to force said second pad in onedirection into contact with one face of the disc and to move the housingin the opposite direction to force said first pad into contact with theother face of the disc and an articulated connection between the housingand a fixed member to enable the housing to move axially orsubstantially axially relative to the disc and at the same time to tiltto accommodate wobbling or oscillation of said disc from said verticalplane. H

The two members may be connected together by a portion extending axiallyadjacent a periphery of the disc, as in a caliper. However to ensureeconomy of weight and materials, and adequate heatdissipation, the twomembers are preferably interconnected at each end only by meansextending adjacent a periphery of the disc.

One of the members on either side of the disc is connected to anon-rotatable part of the wheel assembly through an articulated linkagewhich, upon actuation of the fluid-pressure mechanism, allows themembers to move sufiiciently, substantially-axially and also tiltingly,for full engagement of the friction pads to take place regardless ofoscillation and the like of the disc.

The fluid-pressure operated mechanism may be a piston and cylindermechanism, the cylinder thereof being formed integrally with thereaction member or secured thereto 'and the piston fluid-tightlyslidable inthe cylinder. The side of the piston remote from the cylinderhas associated therewith a pad of friction material adapted tofrictionally engage one face of the disc. The pressure member on theother side of the disc, which is connected to the reaction member, isalso provided with a friction pad to frictionally engage the other sideof the disc. An increase in pressure between the piston and the base ofthe cylinder forces said piston and base mutually apart. the disc, thusforcing the friction pad associated therewith into frictional contactwith the disc. The reaction member simultaneously moves away from thedisc, thus forcing the pressure member towards the disc and the frictionpad associated therewith into frictional contact with the disc. Thisconstruction may alternatively comprise two or more piston and cylindermechanism.

Disc brakes constructed according to the present invention may also beapplied mechanically e. g. as by a hand lever and cable.

In order that the invention shall be more fully described, reference ismade to the accompanying drawings of which:

Figure 1 is a view of a brake disc and disc brake assembly constructedin accordance with the invention,

Figure 2 is a view of the assembly taken in the direction of arrow 2 ofFigure 1,

Figure 3 is a part section of the assembly taken through the line 33 ofFigure l and looking in the direction of the arrows, and

Figure 4 is a scrap section of the assembly taken through the line. 4-4of Figure 1 and looking in the direction of the arrows.

In the embodiment of the invention illustrated in the accompanyingdrawings the brake comprises a pressure members 1 on one side of thedisc 2 having pads of friction material 3 secured thereto tofrictionally engage one face of the disc. Rigidly secured to saidpressure member by members 4 which extend axially adjacent a peripheryof said disc is a reaction member 5 located on the other side of saiddisc and axially-aligned with the member I. Said reaction member isprovided with a twin piston and cylinder mechanism 6 and pads offriction material 7 are associated with said pistons and are adapted tofrictionally contact the adjacent face of the disc.

The reaction member 5 is provided, on its inner side,

The piston is moved towards with a ribbed flange 8 extendingsubstantially inwardly towards the hub of the wheel. At one end of thisflange is provided a hole having a part-spherical periphery and a bush 9having a complementary outer periphery is fitted in said hole. Anaxially extending pin 10 is fitted within said bush, being secured atone end to a non-rotatable part of the wheel assembly. The other end ofthe flange is likewise provided with a hole having a part-sphericalsided bush 11 therein, and a pin 12 extending axially within said bushhas its two ends each secured to one of two arms 13 of a bifurcatedportion of a link 14. The other end of the link is provided with a holehaving a third part-spherical bush 15 fitted therein and through saidbush is fitted an axially-extending pin 16 having one end secured tosaid non-rotatable part of the wheel assembly.

In the operation of the brake, as fluid-pressure is applied behind thepiston 6, as by operation of the brake pedal in the known manner, thefriction pad 7 is forced against the adjacent side of the disc 2. Assoon as this friction pad 7 touches the disc the fluid-pressure in thespace behind the piston 6 causes the reaction member 5 to be moved inthe opposite direction and as the pressure member 1 is rigidly connectedto the reaction member 5, movement of the reaction member away from thedisc causes the pressure member 1 to be drawn towards it, and thefriction pad 3 is accordingly pressed into frictional engagement withthe opposite side of the disc 2. Axial or substantially axial movementof the conjoined members 1 and 5 is made possible by the ability of theflange 8 to pivot about the part-spherical bushes 9 and 15.

The bush 11 permits a limited angular or tilting movement of the flange8 and the associated friction pads 3, 7 and members 1, 5 to allow thepads squarely to press against the sides of the disc 2, espiteoscillation or deviation of the disc from its true vertical plane ofrotation due e. g. to bowing of the axle as a result of cornering orexcessive road camber.

What I claim is:

1. A disc brake assembly for vehicles or the like com prising a discnormally rotatable in a vertical plane, a non-rotatable housing havingmembers on opposite sides of the disc connected together adjacent aperiphery of the disc, friction pads associated with said members tofrictionally engage the braking surfaces of said disc, a mechanism toeffect said frictional engagement, wherein said housing comprises apressure member and a reaction member each extending chordally acrossand on opposite sides of said disc and being joined together at theiropposite ends adjacent the periphery of said disc, said pressure memberhaving one or more friction pads rigidly associated therewith, and saidreaction member having said mechanism axially-slidably associatedtherewith, and having at least one friction pad rigidly associated withsaid mechanism, and wherein said reaction member comprises aradially-inwardly extending flange having at one end thereof apart-spherical hole, a part-spherical bush located in said hole and apin secured to a non-rotatable portion of said vehicle and extendingaxially through said bush, a link associated with the other end of saidflange and extending radially-inwardly therefrom, a part-spherical holein the free end of said link, a part-spherical bush in said hole and apin secured to said non-rotatable portion of said vehicle and extendingaxially through said bush, said link at the end thereof associated withsaid flange being bifurcated to straddle a portion of said flange, afurther part-spherical hole in said flange and lying between saidbifurcation, a part-spherical bush in said hole, and a pin secured insaid bifurcations and passing axially through said latter-namedpart-spherical bush, whereby said reaction member is free to be movedsubstantially axially and angularly with respect to the normal verticalplane of said disc upon actuation of said mechanism.

2. A disc brake assembly for vehicles or the like comprising a discnormally rotatable in a vertical plane, a nonrotata'ble housingcomprising a pressure member and a reaction member axially aligned onopposite sides of the disc and covering only a minor part of the brakingsurface thereof and connected together by means extending axiallyadjacent a periphery of said disc, a first pad of friction materialsecured to the pressure member to frictionally engage one face of thedisc, a second pad of friction material to frictionally engage the otherface of the disc, a fluid pressure operated mechanism associated withthe reaction member to force said second pad in one direction intocontact with one face of the disc and to move the housing in theopposite direction to force said first pad into contact with the otherface of the disc and an articulated connection between the housing and afixed member to enable the housing to move axially relative to the discand at the same time to tilt to accommodate wobbling or oscillation ofsaid disc from said vertical plane, and in which said connectioncomprises a flange portion extending radially-axially of said reactionmember and of substantially ring sector-like form, a part-spherical holein one end of said flange, a part-spherical bush in said hole and a pinextending axially through said bush and secured in a non-rotatableportion of said vehicle or the like, a link secured to the other end or"said flange and extending radially-inwardly thereof, a part-sphericalhole in the free end of said link, a further part-spherical bush in saidhole and a pin extending axially through said further bush and securedin said nonrotatablc portion of said vehicle or the like.

3. A disc brake according to claim 2 wherein said link is secured tosaid flange by a pin secured in a bifurcation of said link straddling aportion of said flange, said pin passing axially through apart-spherical bush disposed in a part-spherical hole in said flange.

References Cited in the file of this patent UNITED STATES PATENTS2,533,186 Bricker et al. Dec. 5, 1950 2,679,303 Wright et al May 25,1954 2,784,811 Butler Mar. 12, 1957

